Saving Django formset with Many to Many Field

I'm building a little app with a formset that lets me enter a number of game scores each linking to a player via a many to many field. I'm having problems getting this to save properly with various errors. Basic code.

The add() method used for associating instances in many-to-many relations takes one or more individual model instances. You cannot pass an entire list/queryset of players, but you can add them one by one:

for player in p:
scoreSave.players.add(player)

Of course this is rather verbose, so you can use python's syntax sugar for calling add() with all instances at once: